EP0133938A2 - Process for preparing amines - Google Patents

Abstract

1. A process for the preparation of an amine from an olefin and ammonia or a primary or secondary amine at from 80 to 400 degrees C and under from 40 to 700 bar in the presence of a zeolite catalyst, wherein a monounsaturated or polyunsaturated olefin of 2 to 10 carbon atoms or a mixture thereof is reacted with ammonia or a primary or secondary amine, or a mixture thereof, in the presence of a borosilicate or borogermanate zeolite of the pentasil type as catalyst, the resulting amine is isolated, and the unreacted starting materials are recycled.

Description

The invention relates to a process for the preparation of amines by addition of ammonia or analogous amines to olefins.

The addition of ammonia or analogous amines to olefins is a reaction which has been known for a long time and has been described many times. A technical implementation has not yet taken place, since only insufficient selectivities and / or catalyst service lives are achieved by the known processes, such as, for example, according to US Pat. No. 2,623,061, US Pat. No. 2,422,631, US Pat PS 3 412 158. The method described in US Pat. No. 4,307,250 is also unsuitable for implementation on an industrial scale. The alumino zeolites used as a catalyst promote strong polymer formation and subsequent coking, which quickly deactivates the catalyst.

It has now been found that long service lives and high selectivity of the catalysts in the preparation of amines from olefins and ammonia or primary or secondary amines at temperatures between 80 ° C and 400 ° C and at pressures between 40 and 700 bar in the presence of a zeolitic Catalysts are achieved if olefin and ammonia or primary or secondary amines or mixtures thereof are reacted in the presence of a borosilicate or borogermanate zeolite of the pentasil type as a catalyst, the amine obtained is separated off and the unreacted starting materials are recycled.

The process according to the invention is characterized in that a high selectivity of the desired reaction product is achieved even with a low excess of ammonia or amine and the dimerization and / or oligomerization of the olefin used is avoided.

One embodiment of this process consists in that ammonia and / or amines are mixed together with olefins in a molar ratio of 1: 1 to 5: 1 and fed to a fixed bed or fluidized bed reactor and at a pressure of 40 to 700 bar, in particular 200 to 300 bar and a temperature of 80 to 400 ° C, in particular from 250 to 350 ° C in the gas phase or in the supercritical state. Another embodiment is that the reaction in the liquid phase is carried out at a pressure of 40 to 80 bar and a temperature of 60 ° C to 120 ° C in a stirred tank, a solid / liquid fluidized bed or a flow tube.

The desired product is obtained from the reaction discharge using known methods, for example distillation or extraction, and If necessary, brought to the desired purity by means of further separation operations. The unreacted input materials are returned to the reactor.

It is possible to use mono- or polyunsaturated olefins with 2 to ₁₀ carbon atoms or mixtures thereof as starting materials. Because of the less pronounced tendency to polymerize, monoolefins are more suitable than di- and polyolefins, but these can also be reacted selectively with the aid of higher excesses of ammonia or amine. The position of the equilibrium and thus the conversion to the desired amine depends very much on the reaction pressure chosen. High pressure favors the addition product, but in general the pressure range up to 300 bar is the optimum for technical and economic reasons. The selectivity of the reaction - in addition to quantities such as excess ammonia / amine and catalyst - is influenced to a high degree by the temperature. Although the reaction rate of the addition reaction increases sharply with increasing temperature, competing cracking and recombination reactions of the olefin are promoted at the same time. The location of the optimum temperature with regard to conversion and selectivity depends on the constitution of the olefin, the amine used and the catalyst and is usually in the range from 250 ° C. to 350 ° C. The dwell time depends on the starting materials and is expediently in the range between fractions of a second and a few minutes.

Borosilicate or borogermanate zeolites of the pentasil type are used as catalysts for the amination of olefins.

Suitable borosilicate zeolites or borogermanate zeolites are synthesized at 90 to 170 ° C under autogenous pressure by using a boron compound, for example H ₃ B0 ₃ with a silicon compound or a germanium compound, preferably highly disperse silicon dioxide and germanium oxide in aqueous amine solution, especially in 1,6-hexanediamine _- or 1,3-propanediamine or triethylenetetramine solution with and without addition of alkali or alkaline earth metal to react.

Such borosilicate zeolites or borogermanate zeolites can also be prepared if the reaction is carried out in ethereal solution, e.g. Diethylene glycol dimethyl ether or in alcoholic solution, e.g. Performs methanol or 1,4-butanediol.

The borosilicate zeolites and borogermanate zeolites thus produced can be isolated after their isolation, drying at 100 to 160 ° C, preferably at about 110 ° C and calcination at 450 to 550 ° C, preferably at about 500 ° C, with a binder in a ratio of 90:10 to 40:60 wt .-% to form strands or tablets. Various aluminum oxides, preferably boehmite, amorphous aluminosilicates with an SiO ₂ / Al ₂ O ₃ ratio of 25:75 to 95: 5, silicon dioxide, preferably highly disperse Si0 ₂ , mixtures of highly disperse Si0 ₂ and highly disperse A1 ₂ 0 ₃ are suitable as binders , highly disperse TiO ₂ and clay. After the shaping, the extrudates or compacts are expediently dried at 110 ° C./16 h and calcined at 500 ° C./16 h.

A special embodiment consists in that the isolated borosillate and / or borogermantzeolite is deformed immediately after drying and is subjected to a caleination for the first time after the deformation.

From the catalyst, which has been shaped into strands, it is possible to obtain fluidized material in the size of 0.1 to 0.8 mm by grinding and sieving.

After deactivation of the zeolitic catalysts by coke separation during the reaction according to the invention, the catalysts can be regenerated in a simple manner by burning off the coke deposit with air or with an air / N ₂ mixture at 400 ° C. to 550 ° C., preferably at about 500 ° C. . This gives you back your initial activity.

To increase the selectivity, the service life and the number of possible regenerations, various modifications can be made to zeolitic catalysts.

A modification of the catalysts is that the undeformed or the deformed zeolites with alkali metals such as Na and K, alkaline earth metals such as Ca, Mg, earth metals such as Tl, transition metals such as Mn, Fe, Mo, Cu, Zn and rare earth metals such as La, _Ce ion noise or doping.

An advantageous embodiment is that the deformed pentasil zeolites are placed in a flow tube and at 20 to 100 ° C, e.g. a halide or a nitrate of the metals described above passes over it. Such ion exchange can e.g. on the hydrogen, ammonium and alkali form of the zeolites.

Another way of applying metal to the zeolites is to use the zeolitic material, e.g. impregnated with a halide, a nitrate or an oxide of the metals described above in aqueous or alcoholic solution.

Both ion exchange and impregnation can be followed by drying or, alternatively, repeated calcination. In the case of metal-doped zeolites, post-treatment with hydrogen and / or with water vapor can be advantageous.

Another possibility for modification consists in subjecting the zeolitic material - deformed or undeformed - to treatment with acids such as hydrochloric, hydrofluoric and phosphoric acids.

A special embodiment consists in treating the zeolitic powder under reflux with hydrofluoric acid 0.001 n to 2 n, preferably 0.05 to 0.5 n, for 1 to 3 hours before it is shaped. After filtering off and washing out, it is dried at 100 to 160 ° C. and calcined at 400 to 550 ° C. Another special embodiment is an HCl treatment of the zeolites after they have been deformed with a binder. Here, the zeolite is treated for 1 to 3 hours between 60 and 80 ° C with a 3 to 25%, in particular with a 12 to 20% hydrochloric acid, then washed out, dried at 100 to 160 ° C and at 400 to 550 ° C calcined.

Another possibility for modification is given by an exchange with ammonium salts, for example with NH ₄ Cl or with mono-, di- or polyamines. Here, the zeolite, which is present in the H form or another ammonium form and deformed with binder, is continuously at 60 to 80 ° C. with 10 to 25%, preferably 20%, NH ₄ Cl solution in a weight-based zeolite / ammonium chloride solution exchanged by 1:15 and then dried at 100 to 120 ° C.

The catalysts can be used as 2 mm to 4 mm strands, as tablets with 3 to 5 mm diameter or as fluidized material with a size of 0.1 to 0.8 mm or as split with 0.5-1 mm diameter for the amination of the Use olefins.

The following examples illustrate the invention.

example 1

Catalyst A is in a hydrothermal synthesis from 64 g Si0 ₂ (highly disperse silica) 12.2 g H ₃ BO ₃ , 800 g of an aqueous 1,6-hexanediamine solution (mixture 50:50 wt .-%) at 170 ° C produced under autogenous pressure in a stirred autoclave. After filtering off and washing out, the crystalline reaction product is dried at 110 ° C./24 h and at 500 ° C./24 h calcined. A pentasil type borosilicate zeolite is obtained which contains 94.2% by weight of SiO ₂ and 2.32% by weight of B ₂ 0 ₃ .

2 mm strands are produced from this zeolite by shaping with boehmite in a weight ratio of 60:40, which are dried at 110 ° C./16 h and calcined at 500 ° C./24 h.

Catalyst B is prepared by treating 50 g of the borosilicate zeolite described above with 140 ml of O, lN HF under reflux for 1 h. After filtration and washing with water, the mixture is dried at 110 ° C./16 h and calcined at 500 ° C./5 h. This product is extruded with boehmite in a ratio of 60:40, dried at 110 ° C./16 h and calcined at 500 ° C./16 h.

Catalyst C is obtained by carrying out an ion exchange with a Na compound at RT on catalyst A, so that the catalyst, after washing out with water and drying at 110 ° C./16 h, has a Na content of 0.32% by weight. having.

10 ml each of the catalysts A, B or C described above are placed in a 0.3 l stirred autoclave and, after sealing, the olefins and ammonia or amines are pressed on. The amount of product used is such that the desired pressure is reached as the intrinsic pressure of the reactants at the selected reaction temperature. The molar ratio of ammonia / amine to olefin is varied from 1: 1 to 5: 1, the reaction time to 30 min. fixed.

The discharge was examined by gas chromatography separately for the liquid and gas phases. The sales listed in Table 1 always refer to the olefin; the selectivities given relate to the main products: ethylamine from ethylene, isopropylamine from propylene, isobutylamine from butene-1, tertiary butylamine from isobutene, isopentylamine from isobutene with methylamine and 1-amino-4 (1-aminoethyl) cyclohexane from 4-vinyl- l-cyclohexene.

Example 2

For a continuous production, a high-pressure reactor with a length of 2 m and an inner diameter of 24 mm is used, which is heated by an aluminum block heater and equipped with triple internal temperature measurement and pressure maintenance. 60 ml of catalyst are installed in each case and the upper part of the reactor tube is filled with porcelain rings. The olefin and amine are fed in from above.

The analysis of the reactor discharges is carried out by gas chromatography and partly additionally carried out by distillation.

The results with the various catalysts are shown in Table 2. Some results have been obtained without intermediate regeneration of the catalyst. Analysis of the catalytic converter, which was removed after 28 days of uninterrupted operation, shows a carbon content of 11.0%.

Example 3

Catalyst D is obtained by treating 50 g of catalyst A with 250 ml of 15% hydrochloric acid under reflux for 1 h, washing Cl-free after filtration, drying at 110 ° C./16 h and calcining at 500 ° C./5 h.

Catalyst E is prepared by impregnating 50 g of catalyst A with 9.4 g of Zn (NO ₃ ) ₃ .6H ₂ O and subsequent calcination at 540 ° C / 2h.

Catalyst F is obtained by stripping the borosilicate zeolite described in Example 1 with a mixture of highly disperse Si0 ₂ and A1 ₂ 0 ₃ (Al ₂ 0 ₃ content = 3.5% by weight) in a weight ratio of 60:40, at 110 ° C / 16 h and calcined at 500 ° C / 16 h.

Catalyst G is obtained by forming the borosilicate zeolite described in Example 1 into strands with a mixture of 90% by weight of highly disperse SiO ₂ and 10% by weight of boehmite in a weight ratio of 60:40, drying at 110 ° C./16 h and at 500 ° C / 16 h is calcined.

A mixture of isobutene and ammonia in a molar ratio of 1: 1.3 over the catalysts A, B, C, D, E, is in a tube reactor (6 mm inner diameter) under isothermal conditions at 300 ° C and a pressure of 300 bar. F and G implemented discontinuously. The reaction products are analyzed in a gas chromatograph.

The test results are summarized in Table 3.

Claims (7)

1. A process for the preparation of amines from olefins and ammonia or primary or secondary amines at temperatures between 80 ° C and 400 ° C at pressures between 40 and 700 bar in the presence of a zeolitic catalyst, characterized in that olefin and ammonia or primary or reacting secondary amines or mixtures thereof in the presence of a borosilicate or borogermanate zeolite of the pentasil type as a catalyst, separating the amine obtained and recycling the unreacted starting materials. 2. The method according to claim 1, characterized in that the catalyst is deformed with a binder and then calcined. 3. The method according to claim 1 and 2, characterized in that the catalyst is subjected to an acid treatment. 4. The method according to claim 1 to 3, characterized in that the catalyst is doped with transition metals. 5. The method according to claim 1 to 3, characterized in that the catalyst is doped with rare earths. 6. The method according to claim 1 to 3, characterized in that the catalyst is doped with alkali, alkaline earth and / or earth metals. 7. The method according to claim 1 to 3, characterized in that the catalyst is used in its ammonium form after treatment with ammonium salts.